Method of joining ends of warp wires in a wire cloth belt

ABSTRACT

THERE IS PROVIDED A METHOD OF JOINING WRAP ENDS IN A WIRE CLOTH BELT EMPLOYING THE USE OF A METAL CARRIER STRAND IN A DIRECTION ACROSS THE WARP INTERPOSED BETWEEN CORRESPONDING ONES OF OPPOSING WARP ENDS, HEATING A BRAZING ALLOY IN PROXIMITY TO THE CARRIER TO CAUSE IT TO FLOW ALONG THE CARRIER BETWEEN THE WRAP ENDS, THE CARRIER HAVING A HIGHER MELTING POINT BUT SUBSTANTIALLY BELOW THE MELTING POINT OF THE WARP, AND SUBSEQUENTLY APPLYING HEAT TO THE CARRIER TO MELT IT OUT WITHOUT GENERATING SUFFICIENT HEAT IN THE WARP ENDS TO DAMAGE THE LATTER.

Jan. 19,1971 c, KELLEY, JR 3,555,665

METHOD OF JOINING ENDS OF WARP WIRES IN A WIRE CLOTH BELT Filed June 2a, 1958 s Sheets-Sheet 1 INVENTOR.

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Jan. 19, 1971 c. KELLEY, JR 3,5

METHOD OF JOINING ENDSOF WARP WIRES IN A WIRE CLOTH BELT Filed June 28. 1968 5 I5 Sheets-Sheet 2 INVENTOR. (f/APLES KELLEV Je ATTORNEY Jan. 19, 1971 c. KELLEY. JR 3,555,565

METHOD OF JOINING ENDS OF WARP WIRES IN A WIRE CLOTH BELT Filed June 28, 1968 v 3 Sheets-Sheet 5 INVENTOR. /9 04442455 K5115) Je BY ML @M United States Patent 3,555,665 METHOD OF JOINING ENDS OF WARP WIRES IN A WIRE CLOTH BELT Charles Kelley, Jr., Woodbridge, Conn., assignor to McCluskey Wire Co., Inc., New Haven, Conn. Filed June 28, 1968, Ser. No. 741,055 Int. Cl. B23k 31/02 US. Cl. 29-4713 6 Claims ABSTRACT OF THE DISCLOSURE There is provided a method of joining warp ends in a wire cloth belt employing the use of a metal carrier strand in a direction across the warp interposed between corresponding ones of opposing warp ends, heating a brazing alloy in proximity to the carrier to cause it to flow along the carrier between the warp ends, the carrier having a higher melting point but substantially below the melting point of the warp, and subsequently applying heat to the carrier to melt it out without generating sufiicient heat in the warp ends to damage the latter.

and be resistant to cracking caused, for example, by the action of corrosive elements to which they may be exposed in a paper-making process. Fourdrinier cloth is composed of relatively fine strands sometimes comprising relatively expensive metal such as stainless steel, for example, woven in relatively fine meshes in the approximate range, for example, of 40 to 80 warp wires to an inch and 36 to 70 shute wires to an inch. It will be obvious from the foregoing that Fourdrinier wire cloth is relatively expensive to produce and quite expensive for a user to replace.

In use Fourdrinier wire cloth has heretofore been best known to give trouble in the area of the seam joining the ends of the wire cloth. Most failures of the cloth result in this area due to cracking of the warp end portions, but the use of modern seaming materials and techniques has done much to lengthen the service life of such cloth.

The main problem, or at least a very significant one, in the use of Fourdrinier wire cloth heretofore has been the change in the drainage characteristics of the cloth in the area of the seam, and, in addition, a tendency of upward plowing of water through the cloth in this area to mark the paper, effected by the techniques most commonly employed in producing such seams. The invention is directed toward the solution of these problems in the area of a seam by utilizing a new method of joining warp ends in a wire cloth belt, which results in a product in which the drainage characteristics of the belt in the area where the Warp ends are joined are substantially the same as the drainage characteristics of the body of the cloth, and there is no water-plowing tendency in this area to mark paper.

Accordingly, one object of the invention is to provide an improved method of joining warp ends in a Fourdrinier wire cloth belt. Another object is to employ in such a method the use of a metal carrier strand in a direction across the warp interposed between corresponding ones of opposing warp ends, heating a brazing alloy in ice proximity to the carrier to cause it to flow along the carrier between the warp ends and subsequently applying heat to the carrier to melt it out without generating sutficient heat in the warp ends to cause them to crack in the use of the belt. Further objects of the invention will be apparent from the following detailed description of the method of joining warp ends.

In the drawings:

FIG. 1 is a fragmentary, greatly enlarged, top plan view illustrating the ends of Fourdrinier wire cloth seamed together by a conventional. technique for joining warp ends;

FIG. 2 is a further enlarged sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is a fragmentary bottom view of the wire cloth shown in FIG. 1 illustrating the seam therein;

FIG. 4 is a sectional view taken on line 4-4 of FIG. 3;

FIG. 5 is a fragmentary, greatly enlarged, top plan view illustrating the joining of warp ends of such cloth in accordance with the method embodying the invention, illustrating a step in this method;

5 Fla}. 6 is a sectional view taken on line 6-6 of FIG.

FIG. 7 is a view similar to FIG. 5 but illustrating the wire cloth as it appears upon completion of the joining of the warp ends in accordance with the invention.

For a better understanding of the invention and drainage problems heretofore encountered in Fourdrinier wire cloth seamed in accordance with a conventional technique, there are illustrated in FIGS. 1 through 4 of the drawings the ends A and B of a piece of wire cloth required to be joined to form a belt for use in a Fourdrinier papermaking machine.

The cloth includes relatively fine strands of wire illus trated as interwoven in a twill weave. The wire strands may be formed, for example, of an alloy such as bronze, of chromium nickel austenitic grades, of Monel or cobaltbased metal. In such cloth warp strands formed of one of these materials may be interspersed with warp strands formed of another of these materials if desired. Also in the illustrated form, the wire strands are round in cross section. Cloth for such use is commonly formed of flat strands. The diameter of the illustrated strands may vary from approximately .0065 to .013 of an inch in difierent cloth constructions while the diameter of the shute strands may range approximately from .00725 to .015 of an inch in different construction. The mesh in different constructions may range from approximately warp strands to an inch to 40, while the shute strands may range from approximately 70 strands to an inch to 36.

In the cloth shown in FIGS. 1 through 4 the warp strands are indicated at 10 while the shute strands are indicated at 11. As shown in FIG. 1, each warp strand 10 passes over one shute strand 11 and then under the next two shute strands 11. Each warp strand has its ends cut perpendicular to the plane of the cloth, as shown in FIG. 2. These cut ends may be smoothed by any conventional technique and the warp ends are brought together as illustrated so that the pattern of the weave is continued across the seam indicated generally at 12 between the ends A and B of the cloth.

In this method of seaming the ends of warp strands, a flat or round ribbon, not shown, is employed to extend in a direction across the Warp interposed between the opposing warp ends. The ribbon in accordance with this technique comprises a bronze core which acts as a carrier for an outer coating of a brazing material or alloy having a substantially lower melting point than the carrier. The brazing material on the carrier is often a silver alloy or gold but may consist of some other suitable metal or combination of metals, usually with a melting point between 1100 F. and 1800 F. However, at the present time the Fourdrinier wire industry has tended to standardize on the use of a brazing material having a melting point of approximately 1200 F. to 1400 F. This is considered a safe temperature range with reference to the warp and makes possible the use of a brazing material having the required tensile strength. In the illustrated embodiment the warp may be considered as consisting of strands of bronze. If such strands are heated excessively during a brazing process to join warp ends, the grain of the metal is subject to change in such manner that in use of the Fourdrinier cloth the end portions of the warp strands are likely to crack, causing failure of the seam. Also, when warp strands formed of stainless steel are heated excessively during a brazing operation, carbide precipitation takes place around the grain of the metal making the metal subject to galvanic or chemical action in use of the cloth which also often results in the failure of the seam. It is for these reasons that the industry has tended to adopt for such use a brazing material having a melting point in the aforementioned range of approximately 1200 F. to 1400 F.

A conventional brazing machine, not shown, may be employed to effect the seam between the ends of the wire cloth. The technique requires that the seaming ribbon be interposed between opposing and aligned ends of the warp strands so as to be contacted thereby. Subsequently, by the use of the brazing machine, the brazing material, which has a substantially lower melting point than the carrier, is fused so that it flows along the carrier on and between the warp ends. The resultant seam has the appearance of that shown in FIG. 1 and, as clearly shown in this view, the seam extending intermediate two shute wires 11 in parallelism thereto is continuous transversely of the cloth, that is to say, that the seam not only join the opposing aligned ends of each warp wire but joins or bridges each warp wire with its neighboring warp wires, thereby substantially closing the mesh in the area of the seam. This closing tendency of the mesh in the area of the seam elfects poorer drainage than in the body of the cloth which is undesirable in the making of paper.

This tendency of the mesh in the area of the seam to close or become finer by reason of the existence of the seam formed in the aforementioned manner cannot be avoided from a practical standpoint. For example, if the cloth is cut, or one or more shute wires are removed from the cloth, to produce longer warp ends these ends would flex too much in use and, when brought toward one another for seaming, would not meet properly. Under such circumstances they would have a tendency to overlap. This overlapping would also effect changes in the drainage characteristics of the wire. Moreover, it has been noted that in the use of the conventional technique described above, the shute wires tend to conduct and dissipate heat from the warp ends. For this reason the removal of one or more shute wires to make the warp ends longer for brazing has been known to result in excessive heating of the warp ends to the extent that they may crack in use of the cloth.

It has also been discovered that, if an attempt is made to improve the drainage characteristics of the wire cloth in the area of the seam 12 by melting out the bridges created by the seam between any two warp wires, as by the use of a brazing machine, the temperature in the warp ends is raised excessively to the point where the seam may fail in use of the cloth. This is due to the relatively high melting point of the seam core which, as previously indicated, is formed of bronze, the same material from which the warp strands are formed.

Apart from the aforementioned disadvantage of the change of drainage characteristics in the wire cloth effected by the above-described seam, a further serious disadvantage has been found in such a seam which is that it may waver up and down with reference to the plane of the cloth as it extends across the warp. A high seam in Fourdrinier wire cloth has seldom been found in use to damage paper unless the seam is relatively very high. However, a low seam such as illustrated in FIGS 1 through 4 may have adverse effects on paper made in a Fourdrinier machine to such an extent as to require replacement of the wire cloth. Paper is marked when a low seam strikes a conventional suction box, not shown, over which the wire cloth moves, causing a plowing effect of water up through the cloth, striking the paper. Such marking requires removal and replacement of the Fourdrinier wire.

The cloth shown in FIGS. 1 through 4 is illustrated as worn to some extent. It has abraded and flattened surfaces 13 on the upper face of the cloth as shown in FIG. 1, which surfaces are found on at least certain of the warp knuckles. The lower face of the cloth is subject to greater abrasion in use. Abraded areas of the warp on this face of the cloth are indicated at 14 as shown in FIG. 3.

In FIG. 2 one of the warp wires 10 is shown in longitudinal section with reference to shute wires 11 in the general area of the seam 12. The silver brazing alloy of the seam between the ends of the warp wire is indicated at 15 and the aforementioned carrier or core is indicated at 16. As shown in this view the seam 12 is a low seam extending down at least to the plane of the flattened surfaces 14 of the warp knuckles and below the lower extremities of the two lower shute knuckles illustrated. It will be noted that the core 16 of the seam is low with reference to the ends of the warp wire shown in this view. That is, the core does not extend upwardly with reference to the warp ends as much asit does in a downward direction. A similar joint between the ends of another warp wire is shown in FIG. 4. This low seam wire, shown in the last-mentioned views, effects bridges between warp Wires, which bridges when they strike suction boxes cause water to be snowplowed into the paper as previously described. These bridges, because they are low, tend to become abraded as indicated at 17 (FIG. 3) where they strike or run over the suction boxes.

To avoid the creation of bridges between warp wires, aside from that described above involving the melting out of the bronze core of the seaming ribbon, which was found to be injurious to the warp ends in the use of the fabric as indicated, it has been proposed in accordance with the disclosure of US. Pat. No. 2,496,052, dated Jan. 31, 1950, to employ as a seaming ribbon for joining warp ends by a brazing process a strand of wire composed of a single metal such as gold. The finished product illustrated in thepatent does not have bridges extending between the warp Wires but no specific information is given as to how these bridges are avoided. Theoretically, metal on the periphery of the seaming ribbon shown in the patent could be fused by a brazing element to an extent causing it to flow along the metal of the inner portion of the ribbon on and between the warp ends to coat them, and then a greater degree of heat could be applied by the brazing element to melt out the central part of the ribbon. However, when attempts have been made to put this theory into practice, the result has been that certain warp ends have been skipped by the brazing material during the fusing process and that the material of the brazing ribbon has tended to pile up on certain warp ends and flow into the mesh, tending to fill it adjacent the area of the lastrmentioned warp ends. In forming the seam disclosed by the patent, it has been found that during the brazing process it has been necessary in order to join the ends of a single warp wire to fuse an entire segment of the ribbon so that the fused metal fiows on and between the warp ends, requiring a high degree of skill on the part of the operator. This has also been found to be a slow process and, in view of the foregoing, wire cloth seamed in this manner is relatively expensive to produce.

Turning now to my improved method of joining warp ends of wire cloth, tending to obviate the aforementioned difficulties with Fourdrinier wire, illustrated in FIGS. 5, 6 and 7, the body of the cloth may be formed as previously described, that is, with warp and shute strands,

shown in a twill weave composed of metal selected, for example, from the previously described group and either of flat or round cross section, the latter being illustrated by way of example. The warp strands are indicated at 18 and the shute strands at 19. They may be in the abovediscussed approximate range of diameters woven in the same approximate range of meshes.

The ends of the cloth, indicated at C and D, are cut in the same manner, and the ends of the warp wires are smoothed. By way of example only, the warp may be considered as constructed of bronze and the shute may be considered as being constructed of the same metal. To join the opposed ends of the warp wires together a flat seaming ribbon 20 is employed in a brazing operation to be described, the ribbon having a cross-sectional width of .00045 of an inch and a cross-sectional length of .016 of an inch for warp of .0073 of an inch in diameter and shute of .00875 of an inch in diameter, all by way of example. The length of the ribbon is in excess of the width of the belt to be formed. The aforementioned crosssectional length of the ribbon 20 is arranged in a plane normal to the plane of the cloth when the ribbon is positioned with reference to the cloth for brazing the ends of the warp wires.

In the illustrated form of the invention, the ribbon 20 comprises an outer coating or layer of brazing material, not shown, which may constitute as little as percent of the volume of the ribbon and as much as '90 percent. However, it has been found that best results have been obtained using a volume of approximately 60 percent of the ribbon. The ribbon comprises a core, not shown, acting as a carrier for the brazing material to control its flow in the fused state during a brazing operation. The volume of the core may vary as indicated above. The presently preferred volume of the ribbon core is approximately 40 percent. The use of these preferred percentages does not require an undue amount of skill on the part of the operator during the brazing process. As previously indicated, a brazing material should be used for joining the warp ends having a melting point between approximately 1100 F. and 1800 F. Also, as previously indicated, the Fourdrinier wire industry as a whole presently prefers for this purpose a brazing material having a melting point in the safe range of approximately 1200 F. to 1400 F., the word safe being with reference to the tensile strength of the material and the avoidance of applying such heat to the warp ends as to cause damage in the use of the cloth as previously explained.

The brazing material may have a melting point of approximately 50 F. to 700 F. below the melting point of the core or carrier. However, I have found that the use of materials having a difference of only 50 F. with reference to their melting points requires an undue amount of skill in brazing, and that a difierence in the melting points of 700 -F. is unnecessary and perhaps not as advantageous as the use of materials having lower differences in melting points. When using a silver alloy as a brazing material, and a somewhat similar alloy as a core or carrier in the ribbon 20, I prefer to use alloys having a difference of approximately 222 F. in their melting points. However, if desired a gold brazing material, for example, may be employed in a brazing ribbon having a gold core or carrier having a higher melting point than the outer cover of the ribbon as indicated.

For example, in the use of a silver alloy for a brazing material to join the ends of the warp wires 18, employing the brazing ribbon 20, I prefer to use as a core for the ribbon a silver alloy composed of approximately 71.8 percent silver and 28.2 percent copper having an approximate melting point of 1434 F., within the safe range, with a silver alloy coating on its periphery composed of approximately 54 percent silver, 23 percent copper and 23 percent zinc having a melting point in the approximate range of 1223 F. to 1245" F. These melting points are not only well below the melting points of the metal or metals of the warp and shute strands of the wire cloth, but are sufiiciently or substantially below the temperatures which would eifect damage to the warp ends by excessive heating. It is to be understood with reference to the appended claims that where reference is made to a brazing material and/or a carrier therefor as having a substantially lower melting point than the metal of the warp strands, it is meant that the fusing of the brazing material and/or the carrier therefor does not require the application of excessive heat to the warp ends such as to be likely to cause them to crack in use of the Fourdrinier wire cloth.

In the brazing process a conventional brazing machine may be employed which is one of the advantages of the invention, if desired. In this process a length of the brazing ribbon 20 is extended between the free, generally opposing ends of the warp wires to be joined together at the ends C and D of the wire cloth. The ends of each of these warp wires are substantially aligned with one another and brought into contact with the ribbon 20. The brazing machine passes lengthwise along the ribbon 20 in a direction across the warp. The heat supplied by the brazing element or tip may be adjusted and set so that as the tip approaches any one of a pair of warp ends to be brazed together sufficient heat is generated to cause the brazing material on the core to begin to fuse and flow therealong on and between the last-mentioned warp ends. The fusing of the brazing alloy on the perihery of the carrier may be complete when the brazing tip reaches the last-mentioned ends of the warp wire, and the heat is sufficient at this point in the travel of the tip to cause the carrier to commence to fuse. The residual heat as the brazing tip leaves the aforementioned pair of warp ends on its travel is sufficient under such circumstances to cause complete fusing of the carrier or core of the ribbon 20, so that metal is deposited only On the warp ends without the creation of a bridge between adjacent warp strands.

The foregoing is well illustrated in FIG. 5 of the draw ings wherein the fused metal of the ribbon has ceased to flow on the warp strand as at 21 so as to solidify thereon. No bridge remains bet-ween this joint and the next warp strand on which the metal of the ribbon may still be in a somewhat fused state, as at 22. Here again, no bridge remains between the joint and the next adjacent warp ends on which the material of the ribbon, particularly the outer layer thereof, is in a fused condition, as at 23, and has not spread to its fullest extent on and between the ends of this warp wire. Here the bridge between the joint and the next adjacent warp wire 18 is fusing or, to state it another way, has not completed fusing. The degree of coating of the warp ends by the brazing material during the grazing process and in the finished product shown in FIG. 7 is exaggerated for the purpose of explaining the method. In actual photomicrographs of the joints between warp ends the coating of brazing material on the warp ends is hardly detectable. It will, therefore, be apparent that the drainage characteristics of the wire cloth at the so-called seam remain substantially unchanged from the drainage characteristics of the body of the cloth. In the finished product shown in FIG. 7, the joints between the warp wires 18 in their brazed and finished state are indicated at 24, and it will be noted that not only are bridges avoided between warp wires in the seam area such as to change drainage characteristics of the wire cloth in this area, but there is nothing remaining in the seam area to extend below the shute wires in such a manner as to strike suction boxes and snowplow water up through the wire cloth to mark paper thereon.

While only one form of the method of joining warp ends has been illustrated and described above, it will be apparent to those versed in the art. that the method may take other forms and is susceptible of various changes without departing from the principles of the invention and the scope of the appended claims.

What I claim is:

1. In the joining of warp ends in a wire cloth belt having metal warp strands interwoven with shute strands, and having a mesh as fine as forty strands per inch, the method comprising the steps of (a) arranging two pieces of the belt, each of which has cut ends of the warp strands, to bring the cut ends of the warp strands in one piece into opposed aligned relation with the cut ends of the warp strands on the other piece and in close proximity thereto,

(b) placing a strand comprising a carrier core of a metal which fuses at a temperature appreciably lower than that of said warp strands and a coating of a brazing material which fuses at a temperature at least 50 lower than the fusing temperature of the core and lower than the fusing temperature of said warp strands across said wire cloth with the strands being interposed and in engagement with said cut ends of the warp strands in opposed aligned relation; and

(c) applying heat progressively along said strand from one side of the wire cloth to the other, said heat being of a temperature which first fuses the brazing material to cause it to flow along the core to the most closely adjacent cut ends of the warp strands and then melt out the carrier core between the warp strands leaving parts of the core in the fused joints.

2. The method of joining warp ends as defined in claim 1 wherein at leastcertain of the warp strands are formed of bronze, are round in cross section and-of a diameter in the approximate range of .013 to .0065 of an inch.

3. The method as defined in claim 1 wherein the coated carrier element constitutes a ribbon in which the carrier element constitutes approximately 40 percent of the ribbon by volume and the coating 60 percent by volume.

4. The method as defined in claim 1 wherein the carrier element is composed of approximately 71.8 percent of silver alloyed with approximately 28.2 percent of copper, the carrier having a melting point of approximately 1434 F and wherein said coating is composed of approximately 54 percent silver alloyed with approximately 23 percent 8 copper and approximately 23 percent Zinc, the coating having a melting point of approximately 1234 F.

5. The method of joining warp ends as defined in claim 1 wherein the coated carrier element constitutes a ribbon flat in cross section having an approximate cross-sectional width of .00045 of an inch and an approximate crosssectional length of .016 of an inch, and wherein the warp strands are found in cross-section and of a diameter of approximately .0073 of an inch and the shute strands are round in cross section and of a diameter of approximately .00875 of an inch.

6. The method as defined in claim 3 wherein the carrier element is composed of approximately 71.8 percent of silver alloyed with approximately 28.2 percent of copper, the carrier having a melting point of approximately 1434 F., and wherein said coating is composed of approximately 54 percent silver alloyed with approximately 23 percent copper and approximately 23 percent zinc, the coating having a melting point of approximately 1234 F.

References Cited UNITED STATES PATENTS 2,061,454 11/1936 Crossman 24510 2,116,811 5/1938 Webb et a1. 245-40 2,141,706 12/1938 Buchanan 24510 2,371,754 3/1945 Gillium et al 29471.3X 2,421,601 6/1947 Dilley et al 24510 2,496,052 1/1950 Hose et al 24510 2,893,664 7/1959 Gerhauser 245-10 3,186,663 6/1965 Godschalx et al 24510 3,392,942 7/1968 Stanton 24510 3,412,458 11/1968 Delnero 24510 3,482,300 12/1969 Reinke 29--471.1X

JOHN F. CAMPBELL, Primary Examiner R. B. LAZARUS, Assistant Examiner US. Cl. X.R. 

